JP2848655B2 - Resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition comprising a modified polyolefin and a saturated polyester. More specifically, the present invention relates to a resin composition having excellent moldability and excellent rigidity, heat resistance, and electrical properties.

Polyolefin-based resins are generally inexpensive, have excellent moldability, have low moisture absorption and low specific gravity, and are widely used in various fields. However, the rigidity at high temperatures is not sufficiently satisfactory in performance. On the other hand, various types of saturated polyester resins have been developed, but generally have excellent heat resistance and oil resistance.
Widely used in the field of electronic components. However, this resin may be difficult to mold due to hydrolysis during molding. Furthermore, there is a drawback that electric characteristics are deteriorated due to hygroscopicity. Therefore,
If a composition having the characteristics of each of the above-mentioned resins and suppressing the defects can be obtained, it can be said that its industrial significance is very large. It is an object of the present invention to provide such a composition.

[Conventional technology]

As a method of combining the advantages of both the polyolefin-based resin and the saturated polyester-based resin as described above and compensating for the disadvantages, it has been studied to use a composition in which both are blended.

However, these polyolefin resins and saturated polyester resins are originally incompatible with each other and have no affinity.
The adhesion at the interface of the phase structure is not good. For this reason, the two-phase interface of the obtained molded product becomes a defect, and the mechanical strength and impact resistance are reduced. Further, the two phases are unlikely to be in a uniform and finely dispersed form, and when subjected to a shearing stress during molding processing such as injection molding, delamination is likely to occur.

In general, when blending these incompatible polymers, one possible way to solve the above problem is to incorporate a third component to improve the affinity between the two components. is there.

For example, a method in which an epoxy group-containing ethylene copolymer is used as a third component in addition to a polyester resin and a polypropylene resin (JP-A-61-60744), a polyester resin and a maleic anhydride-modified polypropylene (JP-A-61-60746), a modified polypropylene resin obtained by graft copolymerization of a polyester resin and an unsaturated epoxy compound, and an epoxy-containing ethylene copolymer (Japanese Unexamined Patent Application Publication No. 1-213352) has been proposed.

However, even in these compositions, the affinity between the modified polypropylene resin and the polyester resin is not sufficient, and it is essential to use an epoxy group-containing ethylene copolymer in combination in order to improve impact strength. However, as a result, the rigidity will be reduced
It has been difficult to balance stiffness and impact resistance at a high level.

[Problems to be solved by the invention]

An object of the present invention is to solve the above-mentioned problems of the prior art without necessarily using a third component in combination, and a polyolefin resin and a saturated polyester resin are homogeneously mixed, and a molding process is performed. The present invention provides a molding resin composition which suppresses delamination, which is often observed when mixing incompatible resins, and has good appearance of a molded article and improved mechanical properties mainly on impact strength. Is to do.

[Means for solving the problem]

The present inventors have conducted intensive studies to achieve the above object, and as a result, blended a polyolefin resin modified with a silicon compound containing a hydrolyzable organic group and a saturated polyester, and a resin obtained by melt-kneading. The composition has been found to be able to achieve the above goals and has reached the present invention.

That is, the present invention provides: (A) a general formula -SiR _n Y _3-n (where R is an aliphatic hydrocarbon group, Y is a hydrolyzable organic group or a hydroxyl group, and n represents 0, 1 or 2) 5 to 95% by weight of at least one type of modified polyolefin resin selected from the group consisting of ethylene homopolymer resins, propylene homopolymer resins, and ethylene-propylene block copolymer resins containing a silicon compound residue represented by
And (B) 95 to 5% by weight of a saturated polyester resin.

In the present invention, it is not always logically clear why the silicon compound having a hydrolyzable organic group or the like as a modifying component of the component (A) is effective, but it is presumed that it will be inferred as follows. Can be It is known that the silicon compound residue undergoes a condensation reaction with itself or a silanol group. Therefore, in the case of the present invention, it is considered that the silicon compound residue is bonded to the hydroxyl group of the saturated polyester resin to form a polyolefin graft polyester type polymer, which contributes to the affinity of both resins.

(A) Modified polyolefin resin component The polyolefin resin modified by the silicon compound having a hydrolyzable organic group, which is the component (A) used in the present invention, can be produced, for example, by the following method. .

That is, an ethylenically unsaturated silane is grafted onto an ethylene-based resin such as a copolymer mainly composed of polyethylene and ethylene, or a propylene-based resin such as a copolymer mainly composed of polypropylene and propylene in the presence of a radical generator. A copolymerization method (see JP-A-48-1711, JP-A-59-36115, etc.) or a high-pressure radical copolymerization of ethylene with an ethylenically unsaturated silane and, optionally, a radical polymerizable monomer. Typically, it is produced by a method (see Japanese Patent Publication No. 23777/1987).

However, in the present invention, the method for producing the modified polyolefin of the component (A) is not limited to the above-described method. For example, a maleic anhydride-modified polyolefin-based resin is reacted with γ-aminopropyltrimethoxysilane. Various methods can be applied, such as a method of obtaining the same. The silicon compound for modification is not limited to ethylenically unsaturated silane.

As the silicon compound for modification, a silicon compound having a reactive group capable of grafting to an olefin polymer, a silicon compound having a group capable of reacting with a functional group introduced into the olefin polymer, or a reactive compound capable of copolymerizing with an olefin monomer There is a silicon compound having a group, etc., and generally includes a compound represented by the following formula: R'SiR _n Y _3-n wherein R 'is, for example, a vinyl group, an allyl group, an isopropenyl group, a butenyl group, a cyclohexenyl group Group or γ-
And a (meth) acryloyloxypropyl group. R is a hydrocarbon group such as an alkyl group such as a methyl group, an ethyl group, a propyl group, and a decyl group. Y represents a hydrolyzable organic group or a hydroxyl group, and n is 0, 1 or 2. Examples of Y include a methoxy group, an ethoxy group, a formyloxy group, an acetoxy group, a propionyloxy group, an alkyl group and an arylamino group.

Particularly preferred as the silicon compound for modification is a compound represented by CH ₂ CHCHSi (OA) ₃ (where A represents an alkyl group having 1 to 8 carbon atoms), specifically, vinyltrimethoxy. Silane and vinyltriethoxysilane.

Examples of the polyolefin resin modified with the silicon compound having a hydrolyzable organic group as described above include homopolymers of α-olefins such as ethylene, propylene, butene, and hexene, and copolymers of these α-olefins. And copolymers of these α-olefins with other unsaturated monomers copolymerizable therewith.

Specifically, low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, propylene-ethylene copolymer, ethylene-vinyl acetate copolymer,
Ethylene- (meth) acrylic acid copolymer and ionic crosslinked product thereof, ethylene- (meth) acrylic acid ester copolymer, and a mixture of these polymers, or the above polymer and maleic anhydride, (meth) acrylic acid,
It also includes a graft copolymer with a (meth) acrylate or the like.

The modified polyolefin resin of the component (A) may be a modified resin alone or a mixture of a modified resin and an unmodified resin. In this case, the mixing ratio of the modified resin and the unmodified resin can be arbitrarily set according to the amount of the modifying agent introduced into the polyolefin resin, the mixing ratio of the polyolefin resin and the saturated polyester resin, and the like.

The amount of the modifier in the component (A) is usually 5% by weight or less, preferably 3 to 0.1% by weight. If the amount of the modifying agent is more than this, in the kneading process of the resin, due to the progress of the crosslinking reaction by the silanol condensation reaction between the modified resins,
In some cases, the processability and mechanical strength of the resulting composition may be reduced.

(B) Saturated Polyester Resin As the saturated polyester resin as the component (B) used in the present invention, various polyesters can be used.

For example, one of them is a thermoplastic polyester resin produced by condensing a glycol with a dicarboxylic acid or a lower alkyl ester or an acid halide or an anhydride derivative thereof according to a usual method.

Aromatic and aliphatic dicarboxylic acids suitable for making this polyester include: That is, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid,
Isophthalic acid, p-carboxyphenoacetic acid, p, p'-dicarboxydiphenylsulfone, p-carboxyphenoxyacetic acid, p-carboxyphenoxypropionic acid, p
Carboxyphenoxybutyric acid, p-carboxyphenoxyvaleric acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid and mixtures of these carboxylic acids are also used.

Aliphatic glycols suitable for the production of polyesters include linear alkylene glycols having 2 to 12 carbon atoms, such as ethylene glycol, 1,3-propylene glycol, 1,4-butene glycol, 1,6-hexene glycol. , 1,12-dodecamethylene glycol.
Examples of the aromatic glycol compound include p-xylene glycol, pyrocatechol, resorcinol, hydroquinone, and alkyl-substituted derivatives of these compounds. Other suitable glycols include 1,4-cyclohexanedimethanol.

Other preferred polyesters include polyesters obtained by ring-opening polymerization of lactones. For example, polyvalolactone, poly (ε-caprolactone) and the like.

Still other preferred polyesters include polymers that form liquid crystals in the molten state (Thermotropic Liquiquid).
d There is polyester as Crystal Polymer (TLCP). Representative polyesters in these categories include Eastman Kodak's X7G, Dartco's Xydar (Xydar), Sumitomo Chemical's Econol, Celanese's Vectra, and the like.

Among the polyesters mentioned as the component (B), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polynaphthalene terephthalate (PEN), poly-1,4-cyclohexane dimethylene terephthalate (PCT), liquid crystalline polyester, etc. Are saturated polyesters particularly suitable for use in the resin composition of the present invention.

The composition of the present invention comprises the components (A) and (B) described above. The mixing ratio of the component (A) and the component (B) is such that the component (A) is 5 to 95% by weight and the component (B) Is in the range of 95 to 5% by weight. Outside this range, the effect of the addition of small amounts of components is low, and it is difficult to obtain a molding resin composition having the characteristics of both resins as the target.

In the present invention, other additional components can be added to the composition comprising the components (A) and (B).
For example, known additives such as an antioxidant, a weather resistance improver, a nucleating agent, a flame retardant, and a slip agent can be used for a polyolefin resin, and a known antioxidant and a weather resistance improver for a saturated polyester resin. Agents, plasticizers, flow improvers, release agents, nucleating agents and the like can be used as additional components.
Furthermore, organic and inorganic fillers and reinforcing agents, especially glass fiber, mica, talc, wollastonite, potassium titanate, calcium carbonate, silica, etc. are effective in improving rigidity, heat resistance, dimensional accuracy, dimensional stability, etc. It is. Known colorants and their dispersants may be used depending on the actual application.

Further, impact strength improvers, for example, a copolymer of an unsaturated epoxy compound and ethylene, or an unsaturated epoxy compound, a copolymer of ethylene and an ethylenically unsaturated compound, a styrene-butadiene copolymer rubber and the same. Hydride, ethylene-propylene- (diene)
Addition of a copolymer rubber, and its modified α, β-unsaturated carboxylic anhydride and modified with unsaturated glycidyl esters and unsaturated glycidyl ethers is effective for improving the impact strength of the composition. is there.

The amount of the impact resistance improver varies depending on the target physical properties. For example, when the balance between the rigidity of the composition and the impact strength is improved, 5 to 30 parts per 100 parts by weight of the resin component of the composition is used. It is preferred to add parts by weight.

The resin composition of the present invention can be prepared by a method in which the above-mentioned components are kneaded and mixed with various kneaders, for example, a single-screw extruder, a twin-screw extruder, a Banbury mixer and the like. The order of mixing may be in any possible order, but in the case of mixing by a melt-kneading method, a method of sequentially mixing components having a higher viscosity is a preferable method.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited thereto.

[Examples 1 to 10] The components used in the examples are as follows.

(Modified polypropylene) 100 parts by weight of powdery isotactic polypropylene having a density of 0.90 g / cm ³ and a melt flow index of 0.2 g / 10 minutes, 0.5 parts by weight of benzoyl peroxide, 3 parts by weight of vinyltrimethoxysilane, an antioxidant 0.2 parts by weight of tetrakis- [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane is mixed with a mixing stirrer for 2 minutes, and then an extruder having an inner diameter of 40 mm and L / D23 is used. At 210 ° C. to obtain a silane graft-modified polypropylene. The melt flow index of this modified polypropylene was 10.5 g / 10 minutes, and the content of vinyltrimethoxysilane was 2.6% by weight.

(Modified polyethylene) A high-density polyethylene having a density of 0.94 g / cm ³ and a melt flow index of 1.0 g / 10 minutes was melt-mixed in the same manner as the above-mentioned modified polypropylene to obtain a silane-grafted polyethylene.

The melt flow index of this modified polyethylene is
1.4 g / 10 min, the content of vinyltrimethoxysilane is
It was 2.5% by weight.

(Propylene-ethylene block copolymer) A propylene-ethylene block copolymer (trade name: Mitsubishi Polypro BC8D) manufactured by Mitsubishi Yuka Co., Ltd. was used.

(Saturated polyester) Polybutylene terephthalate (trade name: Novador 5010) manufactured by Mitsubishi Kasei Co., Ltd., polyethylene terephthalate (trade name: RT580CA) manufactured by Nihon Unipet Co., Ltd., liquid crystalline polyester manufactured by Celanese Corporation (trade name: Vectra A950)
Were used.

(Preparation of test piece) A resin selected from the above-mentioned modified polypropylene, modified polyethylene and saturated polyester was mixed at a rate shown in Table 1 at a temperature 20 ° C. higher than the melting point of each polyester, TEX30 type manufactured by Nippon Steel Works. The mixture was extruded with a twin-screw kneader, cooled with water, and pelletized. The pellets were dried for 12 hours using a vacuum dryer set at 120 ° C., and thereafter, test pieces for evaluating physical properties were prepared and evaluated using an injection molding machine. The results are shown in Table 1.

[Comparative Examples 1 to 9] Isotactic polypropylene having a density of 0.9 g / cm ³ and a melt flow index of 12 g / 10 minutes, a high-density polyethylene having a density of 0.94 g / cm ³ and a melt flow index of 0.8 g / 10 minutes and the above Examples The saturated polyester shown in the section of
Each was mixed at the ratios shown in Table 2, melt-kneaded under the same conditions as in the examples to prepare test pieces, and the physical properties were evaluated. The results are shown in Table 2.

[Comparative Examples 10 and 11] The physical properties when the modified polyolefin and the saturated polyester used in the examples were each used alone were as follows.
It is shown in the table.

The methods for evaluating physical properties in Examples and Comparative Examples are as follows.

[Preparation of test pieces for evaluation]

Using a Meiki Seisakusho M40A-SJ injection molding machine, injection molding was performed under the conditions of a cylinder temperature 20 ° C. higher than the melting point of each saturated polyester used and a mold cooling temperature of 60 ° C. to produce a test piece.

The test specimen is placed in a desiccator immediately after molding, and 4 to 6 at 23 ° C.
After standing for a day, the evaluation was performed.

(Flexural modulus) Measured using an Instron tester according to JIS K7203.

(Izod Impact Strength) According to ISO R180-1969 (JIS K7110), a notched Izod impact strength was measured using an Izod impact tester manufactured by Toyo Seisakusho.

(Water Absorption) The rate of weight change of the injection-molded test piece after being allowed to stand in an atmosphere at a temperature of 23 ° C. and a humidity of 50% for 20 days was measured.

(Laminar peeling) The gate portion of the injection-molded test piece was bent by hand, and the state of the fracture surface was visually observed to determine the presence or absence of laminar peeling. The judgment is shown by the following three types.

：: No peeling △: Partial peeling ×: Layered peeling [Effects of the Invention] The resin composition according to the present invention, by using a specific modified polyolefin as shown in the examples, not only suppresses delamination, but also the physical properties of molded articles, the composition shown in the comparative example It has a remarkable effect in that various properties which are much better than those of the product can be obtained.

Accordingly, the novel resin composition provided by the present invention can be easily molded by a molding method usually used for thermoplastic resins, for example, injection molding, extrusion molding, a molding method such as hollow molding, a film, A product that is processed into a sheet or the like and has excellent uniformity and smoothness in appearance, and has an extremely good balance of physical properties such as rigidity, heat resistance, impact resistance, chemical resistance, and water resistance can be provided.

Continuation of the front page (56) References JP-A-62-141056 (JP, A) JP-A-56-8446 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 23 / 00-23/36 C08L 67/00-67/04

Claims (1)

(57) [Claims] (A) General formula -SiR _n Y _3-n (where R represents an aliphatic hydrocarbon group, Y represents a hydrolyzable organic group or a hydroxyl group, and n represents 0, 1 or 2) 5 to 95% by weight of at least one modified polyolefin resin selected from the group consisting of an ethylene homopolymer resin containing a silicon compound residue represented by, a propylene homopolymer resin and an ethylene-propylene block copolymer resin,
And (B) 95 to 5% by weight of a saturated polyester resin.